A Camp Pendleton Marine is being awarded the Silver Star for his service in Sangin, Afghanistan. Sgt. Ryan Sotelo, 29, of San Mateo, will be issued the nation’s third-highest honor for valor in combat during a ceremony at the Marine Corps base on Friday.

The former squad leader with 2nd Platoon, Kilo Company, 3rd Battalion, 5th Marine Regiment took charge On Thanksgiving Day 2010 after his platoon commander was fatally shot, according to the citation released Friday.

Sotelo was unavailable to comment about his Silver Star, but U-T San Diego spent more than two weeks with his battalion in Afghanistan last year.

At the time, he recounted the firefight that had occurred a few months before. He remembered calling to the Marine commander prone in the dirt, as the others laid down suppressive fire.

“Get up! We got you,” they yelled. But he didn’t move.

Sotelo and an engineer, Sgt. Patrique Fearon, sprinted to him through bursts of enemy machine-gun fire.

1st Lt. William Donnelly, the 27-year-old officer in charge of their platoon, had been excited to set out that day at dawn to hunt for a Taliban commander’s house. He wanted the squad to “smack the enemy in the face and let them know they couldn’t keep attacking (patrol base) Transformer,” Sotelo recalled.

Finding him motionless on the ground was a shock. They had no time to dwell on it just then. But Donnelly was more than their commander. He was a good friend, a likable guy who was always laughing. He would buy rice and potatoes from the locals to supplement their packaged rations and cook it up in the grimy little power station they called home.

Sotelo and Fearon dragged Donnelly’s body into the cover of a ditch while enemy fighters continued their barrage. “They were right on top of us,” Sotelo recalled. “It was getting bad real fast.” Sotelo led the Marines out of the ambush. They fought almost a mile back to base carrying his lifeless body.

On the way, the squad ducked into a compound and startled several insurgents hiding in the garden.

“When one enemy began to fire on an exposed Marine, Sgt. Sotelo closed on the insurgent and killed him with a grenade,” his citation says.

When they attempted to cross the last stretch of no man’s land to their patrol base, the enemy attacked from all directions. “They just opened up on us, from everywhere, 360 degrees,” Sotelo said.

His citation says: “Realizing that his situation was dire, Sgt. Sotelo led a fighting withdrawal more than 600 meters through enemy fire to bring his squad back to friendly lines.”

“We were returning fire. Then (the enemy) started shooting at the helicopters,” he recalled. After a few gun runs from the sky, the shooting became sporadic enough for them to cross the open field to safety and evacuate the casualties.

During their tour that ended last spring, the 3rd Battalion, 5th Marine Regiment suffered the heaviest casualties of any unit in the war, according to then-Defense Secretary Robert Gates, who visited them in Sangin.

Their battalion of about 1,000 men saw 25 killed in seven months and close to 200 wounded, many with multiple limbs lost and other grave injuries.

The “Darkhorse” battalion had been tasked with helping subdue the insurgent-held crossroads town when it was heavily dug-in with roadside bombs and surrounded by fields of opium poppy. Sangin had been patrolled for several years by British forces until a Twentynine Palms infantry unit — the 3rd Battalion, 7th Marine Regiment — took command a few weeks before the 3/5 Marines arrived in September 2010.

Sotelo lost several other good friends on that tour. Along with his wedding date tattooed on his hand, he carried one dead Marine’s dog tags with him to war each day, and a photo of another tucked into his flak jacket.

There was pride in the changes they wrought in Sangin, if not solace at the heavy cost. Fighting continued after the battalion left and other Marines took over. But the main road through town was open to traffic and insurgents rarely attacked with small-arms fire as Sotelo finished his tour.

“From when we first got here to the way it is now, it’s a complete 180,” Sotelo said in late February 2011. “From getting contact every single day, having to fight your way outside the wire, to now I can walk from (forward operating base) Inkerman all the way down to (patrol base) Transformer on a stretch of road that was never drivable.”

That 20-minute stroll was unthinkable when Sotelo arrived. Supplies had to be airdropped to their patrol base because the roads were insurgent minefields. “It’s a pretty big victory for us,” Sotelo said.

He enlisted in the Marine Corps in 2005 after working as an emergency medical technician and studying firefighting in college. Now Sotelo is assigned to Weapons Company, 3rd Battalion, 5th Marines and is enrolled in the Basic Scout Sniper’s Course.

In addition to the Silver Star, his awards include the Marine Corps Good Conduct Medal second award, Combat Action Ribbon, Navy and Marine Corps Achievement Medal, and Navy and Marine Corps Commendation Medal.